Is working at an association that lends to small-scale manufacturers with interest rates of 17%, which is its sole source of income from which salaries are paid, considered unlawful, taking into account that I possess sufficient savings for my family and me for years?

It is not permissible to work for this association because its work is based on lending with interest (riba), which is one of the gravest major sins and an open declaration of war against Allah. Allah Almighty said: "O you who have believed, fear Allah and give up what remains [due to you] of interest, if you should be believers. And if you do not, then be informed of a war [against you] from Allah and His Messenger. But if you repent, you may have your principal - [thus] you do no wrong, nor are you wronged." You must immediately stop working and look for another job, for whoever fears Allah - He will make for him a way out and provide for him from where he does not expect.